DARK MATTER DENSITY AS A FUNCTION OF THE TIME OF YEAR

2013 ◽  
Vol 28 (27) ◽  
pp. 1330022
Author(s):  
ORVIN E. WAGNER

Until recently I had been assuming from the data taken that the dark matter wave velocity on earth is close to 25 m/s. The density of dark matter is apparently proportional to the reciprocal of the wave velocity squared. I found velocities for 2011 using my interchange method described in my 2010 Physics Essays' article. The data therein was taken near the first of May 2009. Beginning in September 2011, the large amplitude wave velocity was found near 1000 m/s, and increased to more than 20,000 m/s in October in the Northern hemisphere. Apparently one has to take into account the location and tilt of the earth in the dark matter standing wave pattern produced by the sun. I assume that the earth lies at least partially on an antinode for part of the year rather than on a node compared to most of the other planets. The antinode location and dark matter density varies on the earth's surface because the earth's orbit location and tilt varies as a function of the time of year with the tilt determining spring, summer, and winter in the Southern and Northern hemispheres.

2016 ◽  
Vol 458 (4) ◽  
pp. 3839-3850 ◽  
Author(s):  
Qiran Xia ◽  
Chao Liu ◽  
Shude Mao ◽  
Yingyi Song ◽  
Lan Zhang ◽  
...  

2010 ◽  
Vol 514 ◽  
pp. A47 ◽  
Author(s):  
S. Pasetto ◽  
E. K. Grebel ◽  
P. Berczik ◽  
R. Spurzem ◽  
W. Dehnen

2014 ◽  
Vol 10 (S306) ◽  
pp. 258-261
Author(s):  
Metin Ata ◽  
Francisco-Shu Kitaura ◽  
Volker Müller

AbstractWe study the statistical inference of the cosmological dark matter density field from non-Gaussian, non-linear and non-Poisson biased distributed tracers. We have implemented a Bayesian posterior sampling computer-code solving this problem and tested it with mock data based onN-body simulations.


2016 ◽  
Vol 456 (4) ◽  
pp. 3542-3552 ◽  
Author(s):  
Edouard Tollet ◽  
Andrea V. Macciò ◽  
Aaron A. Dutton ◽  
Greg S. Stinson ◽  
Liang Wang ◽  
...  

2020 ◽  
Vol 495 (4) ◽  
pp. 4828-4844 ◽  
Author(s):  
Rui Guo ◽  
Chao Liu ◽  
Shude Mao ◽  
Xiang-Xiang Xue ◽  
R J Long ◽  
...  

ABSTRACT We apply the vertical Jeans equation to the kinematics of Milky Way stars in the solar neighbourhood to measure the local dark matter density. More than 90 000 G- and K-type dwarf stars are selected from the cross-matched sample of LAMOST (Large Sky Area Multi-Object Fibre Spectroscopic Telescope) fifth data release and Gaia second data release for our analyses. The mass models applied consist of a single exponential stellar disc, a razor thin gas disc, and a constant dark matter density. We first consider the simplified vertical Jeans equation that ignores the tilt term and assumes a flat rotation curve. Under a Gaussian prior on the total stellar surface density, the local dark matter density inferred from Markov chain Monte Carlo simulations is $0.0133_{-0.0022}^{+0.0024}\ {\rm M}_{\odot }\, {\rm pc}^{-3}$. The local dark matter densities for subsamples in an azimuthal angle range of −10° < ϕ < 5° are consistent within their 1σ errors. However, the northern and southern subsamples show a large discrepancy due to plateaux in the northern and southern vertical velocity dispersion profiles. These plateaux may be the cause of the different estimates of the dark matter density between the north and south. Taking the tilt term into account has little effect on the parameter estimations and does not explain the north and south asymmetry. Taking half of the difference of σz profiles as unknown systematic errors, we then obtain consistent measurements for the northern and southern subsamples. We discuss the influence of the vertical data range, the scale height of the tracer population, the vertical distribution of stars, and the sample size on the uncertainty of the determination of the local dark matter density.


2014 ◽  
Vol 89 (6) ◽  
Author(s):  
Thomas Lacroix ◽  
Céline Bœhm ◽  
Joseph Silk

2012 ◽  
Vol 425 (2) ◽  
pp. 1445-1458 ◽  
Author(s):  
Silvia Garbari ◽  
Chao Liu ◽  
Justin I. Read ◽  
George Lake

2010 ◽  
Vol 523 ◽  
pp. A83 ◽  
Author(s):  
P. Salucci ◽  
F. Nesti ◽  
G. Gentile ◽  
C. Frigerio Martins

2016 ◽  
Vol 459 (4) ◽  
pp. 4191-4208 ◽  
Author(s):  
H. Silverwood ◽  
S. Sivertsson ◽  
P. Steger ◽  
J. I. Read ◽  
G. Bertone

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